U.S. patent application number 15/801758 was filed with the patent office on 2018-07-19 for friction coefficient measurement apparatus.
This patent application is currently assigned to NIPPO SANGYO CO., LTD.. The applicant listed for this patent is NIPPO SANGYO CO.,LTD.. Invention is credited to Hironari ABE, Kosuke ABE, Noboru ISHIKAWA.
Application Number | 20180202917 15/801758 |
Document ID | / |
Family ID | 60473334 |
Filed Date | 2018-07-19 |
United States Patent
Application |
20180202917 |
Kind Code |
A1 |
ABE; Hironari ; et
al. |
July 19, 2018 |
FRICTION COEFFICIENT MEASUREMENT APPARATUS
Abstract
An object of the present invention is to provide a friction
coefficient measurement apparatus which measures an angle of
relative torsion caused by a friction between a road surface
friction measuring rubber attached strip and a road surface and the
friction coefficient measurement apparatus which is able to reduce
operator taken for work of replacing the road surface friction
measuring rubber attached strip with new one. A friction
coefficient measurement apparatus (100) according to the present
invention includes a road surface friction measuring rubber
attached strip (30) and an attaching bolt (31) which attaches said
rubber attached strip (30)(to a main body of the friction
coefficient measurement apparatus), a diameter of a large-diameter
circular part of an attaching bolt insertion opening (30A) in said
rubber attached strip (30) is set (slightly) larger than a diameter
of a bolt head of the attaching bolt (31) and a diameter of a
small-diameter circular part thereof is set smaller than the
diameter of the bolt head of the attaching bolt (31) and is
(slightly) larger than the diameter of the bolt shaft thereof, and
a spring washer for anti-loosening the attaching bolt (32) and a
rubber attached strip fall prevention washer (33) are
interposed.
Inventors: |
ABE; Hironari;
(Kokubunji-shi, JP) ; ABE; Kosuke; (Kokubunji-shi,
JP) ; ISHIKAWA; Noboru; (Sapporo-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIPPO SANGYO CO.,LTD. |
Kokubunji-shi |
|
JP |
|
|
Assignee: |
NIPPO SANGYO CO., LTD.
Kokubunji-shi
JP
|
Family ID: |
60473334 |
Appl. No.: |
15/801758 |
Filed: |
November 2, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16B 21/09 20130101;
F16B 2001/0035 20130101; F16B 43/003 20130101; F16B 5/0642
20130101; G01N 19/02 20130101 |
International
Class: |
G01N 19/02 20060101
G01N019/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2016 |
JP |
2016-252341 |
May 12, 2017 |
JP |
2017-95722 |
Claims
1. A friction coefficient measurement apparatus comprising: a road
surface friction measuring rubber attached strip; and an attaching
bolt which attaches the road surface friction measuring rubber
attached strip to the friction coefficient measurement apparatus,
wherein an attaching bolt insertion opening is formed in the road
surface friction measuring rubber attached strip, the attaching
bolt insertion opening has a shape formed by overlapping circles of
different diameter sizes, a diameter of a large-diameter circular
part is set larger than a diameter of a bolt head of the attaching
bolt and a diameter of a small-diameter circular part is set
smaller than the diameter of the bolt head of the attaching bolt
and larger than a diameter of a bolt shaft, and a rubber attached
strip fall prevention washer is interposed between an attaching
bolt anti-loosening spring washer and the bolt head of the
attaching bolt, the rubber attached strip fall prevention washer is
formed into an annular shape, a notch is formed therein and a
plurality of projections which project outward in a radius
direction are formed thereon, an opening size of said notch is set
smaller than an outer diameter of the shaft of the attaching bolt
and a maximum distance between leading ends of the projections is
set larger than a large diameter of the attaching bolt insertion
opening formed in the road surface friction measuring rubber
attached strip.
2. A friction coefficient measurement apparatus comprising: a road
surface friction measuring rubber attached strip; and an attaching
bolt which attaches the road surface friction measuring rubber
attached strip to the friction coefficient measurement apparatus,
wherein an attaching bolt insertion slit is formed in the road
surface friction measuring rubber attached strip, the attaching
bolt insertion slit is formed from one side surface toward the
center side of the road surface friction measuring rubber attached
strip, the attaching bolt insertion slit is set to a width size
which is smaller than a diameter of a bolt head of the attaching
bolt and is larger than a diameter of a bolt shaft thereof and is
set into a semicircular shape a diameter size of which is smaller
than the diameter of the bolt head of the attaching bolt and is
larger than the diameter of the bolt shaft of the attaching bolt on
the widthways center of the road surface friction measuring rubber
attached strip.
3. The friction coefficient measurement apparatus according to
claim 1, wherein the road surface friction measuring rubber
attached strip is constructed by a magnetic body and a rubber
attached strip holding magnet is provided in the vicinity of the
attaching bolt.
4. The friction coefficient measurement apparatus according to
claim 1, further comprising an inclinometer which measures an
inclination.
5. The friction coefficient measurement apparatus according any
claim 1, further comprising a counter.
6. The friction coefficient measurement apparatus according to
claim 1, further comprising a satellite positioning system.
7. The friction coefficient measurement apparatus according to
claim 1, further comprising a road surface temperature measurement
device which measures a road surface temperature.
8. The friction coefficient measurement apparatus according to
claim 2, wherein the road surface friction measuring rubber
attached strip is constructed by a magnetic body and a rubber
attached strip holding magnet is provided in the vicinity of the
attaching bolt.
9. The friction coefficient measurement apparatus according to
claim 2, further comprising an inclinometer which measures an
inclination.
10. The friction coefficient measurement apparatus according to
claim 2, further comprising a counter.
11. The friction coefficient measurement apparatus according to
claim 2, further comprising a satellite positioning system.
12. The friction coefficient measurement apparatus according to
claim 2, further comprising a road surface temperature measurement
device which measures a road surface temperature.
Description
TECHNICAL FIELD
[0001] The present invention relates to an apparatus for measuring
a friction coefficient of a road surface and, in more detail,
relates to a friction coefficient measurement apparatus for
measuring an angle of relative torsion caused by a friction between
a road surface friction measuring rubber attached strip and a road
surface.
BACKGROUND ART
[0002] Such a friction coefficient measurement apparatus as
mentioned above is proposed by the applicant of the present
application (see Patent Literature 1) and is a measurement
apparatus which accurately measures a friction coefficient over a
wide velocity range from a high velocity to a low velocity and
which is easy to carry to a measurement site.
[0003] A strip to which road surface friction measuring rubber is
attached (hereinafter, referred to as the road surface friction
measuring rubber attached strip) of this friction coefficient
measurement apparatus is a consumption article and it is requested
to exchange the strip with new one every time in a case that the
rubber has been worn down due to friction between the rubber and
the road surface.
[0004] When exchanging the road surface friction measuring rubber
attached strip with the new one, first, an attaching bolt which is
disposed on one end of the road surface friction measuring rubber
attached strip is detached (unscrewed) from a main body of the
friction coefficient measurement apparatus. Then, the road surface
friction measuring rubber attached strip that a rubber part has
been worn down is exchanged with the new one (another road surface
friction measuring rubber attached strip that the rubber part is
not worn down) and the new one is attached to the main body of the
friction coefficient measurement apparatus by screwing the
attaching bolt into the friction coefficient measurement apparatus
main body.
[0005] Here, since the attaching bolt is comparatively small,
procedure of detaching the attaching bolt from the friction
coefficient measurement apparatus main body and screwing the
attaching bolt again into the apparatus main body are complicated.
Then, it is necessary to store the attaching bolt which has been
detached from measurement apparatus main body somewhere while
exchanging the road surface frictional measuring rubber attached
strip with the new one and labor taken for performing the work is
increased by such the necessity.
[0006] Further, it sometimes occurs that the attaching bolt which
has been detached from the measurement apparatus main body is
fallen downwardly when exchanging the road surface frictional
measuring rubber attached strip with the new one. There are many
cases where measurement of the friction coefficient using the
above-mentioned friction coefficient measurement apparatus is
carried out at night, and then, it is difficult to find the
attaching bolt in a case that the attaching bolt has been fallen
downwardly at night.
[0007] Accordingly, although there is a request to reduce the
operator taken for performing the procedures of exchanging the road
surface friction measuring rubber attached strip with the new one,
a technology which is able to apply to such a request has not been
proposed yet.
PRIOR ART LITERATURE
Patent Literature
[0008] [Patent Literature 1] Japanese Examined Patent Application
Publication No. S57-23212
SUMMARY OF INVENTION
Problems to be Solved by Invention
[0009] The present invention has been made in view of the
above-mentioned issues of related art and aims to reduce the
operator taken for performing the work of exchanging the road
surface friction measuring rubber attached strip with the new one
in the friction coefficient measurement apparatus which measures
the angle of relative torsion caused by a friction between a road
surface friction measuring rubber attached strip and a road
surface.
Constructions of the Invention
[0010] In a friction coefficient measurement apparatus (100)
according to the present invention, characterized in that the
friction coefficient measurement apparatus comprises
[0011] a road surface friction measuring rubber attached strip (30:
a rubber attached strip) and
[0012] an attaching bolt (31) which attaches the road surface
friction measuring rubber attached strip (30) (to a main body of
the friction coefficient measurement apparatus 100); that
[0013] an attaching bolt insertion opening (30A) is formed in the
road surface friction measuring rubber attached strip (30), the
attaching bolt insertion opening (30A) has a shape formed by
overlapping circles of different diameter sizes, a diameter of a
large-diameter circular part (30AA) is set so as to be (slightly)
larger than a diameter of a bolt head of the attaching bolt (31)
and a diameter of a small-diameter circular part (30AB) is set so
as to be smaller than the diameter of the bolt head of the
attaching bolt (31) and (slightly) larger than a diameter of a bolt
shaft thereof; and that
[0014] a washer for preventing the rubber attached strip from
falling (33: hereinafter, referred to as a rubber attached strip
fall prevention washer) is interposed between a spring washer (32:
an existing spring washer) for anti-loosening the attaching bolt
(31), the rubber attached strip fall prevention washer (33) is
formed into an annular shape, a notch (33A) is formed therein (in a
circumferential direction) and a plurality of projections (33B)
which project outward in a radius direction are formed thereon, an
opening size (L1) of said notch (33A) is set so as to be (slightly)
smaller than an outer diameter of the shaft of the attaching bolt
(31) and a maximum distance (L2) between leading ends of the
projections (33B) is set so as to be larger than a large diameter
of the attaching bolt insertion opening (30A) formed in the road
surface friction measuring rubber attached strip (30).
[0015] Also, in the friction coefficient measurement apparatus
(101) according to the present invention, characterized in that the
friction coefficient measurement apparatus comprises
[0016] a road surface friction measuring rubber attached strip (50:
a rubber attached strip) and
[0017] the attaching bolt (31) which attaches the road surface
friction measuring rubber attached strip (50) (to a main body of
the friction coefficient measurement apparatus 101); and that
[0018] an attaching bolt insertion slit (50A) is formed in the road
surface friction measuring rubber attached strip (50), the
attaching bolt insertion slit (50A) is formed from one side surface
toward the center side of the road surface friction measuring
rubber attached strip (50) (and is formed in a direction vertical
to a longitudinal direction of the road surface friction measuring
rubber attached strip 50), the attaching bolt insertion slit (50A)
is set so that a width size of which is smaller than a diameter of
a bolt head of the attaching bolt (31) and is (slightly) larger
than a diameter of a bolt shaft thereof, and (the attaching bolt
insertion slit 50A) is set so that a semicircular shape thereof has
a diameter size which is smaller than the diameter of the bolt head
of the attaching bolt (31) and is (slightly) larger than the
diameter of the bolt shaft thereof on the widthways center of the
road surface friction measuring rubber attached strip (50).
[0019] In the present invention, it is preferable that the road
surface friction measuring rubber attached strip (30, 50) is
constructed by a magnetic body (for example, iron) and a rubber
attached strip holding magnet (34) be provided in the vicinity of
the attaching bolt (31).
[0020] In addition, in the present invention, it is preferable to
include an inclinometer (41) which measures an inclination (of the
friction coefficient measurement apparatus 100, 101).
[0021] In this case, it is preferable to include an electromagnetic
brake (42) (having a function of stopping the operation of the
friction coefficient measurement apparatus 100, 101).
[0022] Then, in the present invention, it is preferable to include
a counter (43) (having a function of measuring and displaying the
number of operations or the number of measurements of the friction
coefficient measurement apparatus 100, 101).
[0023] Further, in the present invention, it is preferable to
include a satellite positioning system (44: for example, a global
positioning system: GPS).
[0024] In addition, in the present invention, it is preferable to
include a road surface temperature measurement device (45) which
measures a road surface temperature.
Effects of the Invention
[0025] According to the present invention having the
above-mentioned constructions, in the road surface friction
measuring rubber attached strip (30: the rubber attached strip),
the attaching bolt (31) is inserted through the large-diameter
circular part (30AA) of the attaching bolt insertion opening (30A)
formed in the road surface friction measuring rubber attached strip
30) and the road surface friction measuring rubber attached strip
(30) is engaged with (locked to) the attaching bolt (31) without
unscrewing and detaching the attaching bolt (31) from the main body
of the friction coefficient measurement apparatus (100). Then, the
road surface friction measuring rubber attached strip (30) is moved
relative to the attaching bolt (31) so as to position the shaft of
the attaching bolt (31) in the small-diameter circular part (30AB)
of the attaching bolt insertion opening (30A) and the attaching
bolt (31) is fastened (engaged). Thereby, it is possible to attach
the road surface friction measuring rubber attached strip (30) to
the main body of the friction coefficient measurement apparatus
(100).
[0026] On the other hand, when friction measuring rubber (30B) of
the road surface friction measuring rubber attached strip (30) has
been worn down, the attaching bolt (31) is loosened (unscrewed) in
a range that it is not detached from the main body of the friction
coefficient measurement apparatus (100), the road surface friction
measuring rubber attached strip (30) that the friction measuring
rubber (30B) thereof has been worn down is moved so as to position
the bolt head of the attaching bolt (31) in the large-diameter
circular part (30AA) of the attaching bolt insertion opening (30A).
In this state, it is possible to detach the road surface friction
measuring rubber attached strip (30) that the friction measuring
rubber (30B) thereof has been worn down from the main body of the
friction coefficient measurement apparatus (100).
[0027] Also, according to the present invention, in the road
surface friction measuring rubber attached strip (50: the rubber
attached strip), the shaft of the attaching bolt (31) is inserted
through an end opening of the attaching bolt insertion slit (50A)
formed in the road surface friction measuring rubber attached strip
(50), the road surface friction measuring rubber attached strip
(50) is moved relative to the attaching bolt (31) (the shaft of the
attaching bolt 31 is relatively moved along the attaching bolt
insertion slit 50A) so as to position the shaft of the attaching
bolt (31) on the widthways center of the road surface friction
measuring rubber attached strip (50) (the attaching bolt 31 abuts
to the center-side end of the attaching bolt insertion slit 50A and
is positioned) and the attaching bolt (31) is fastened, the
attaching bolt (31) is screwed, and thereby, it is possible to
attach the road surface friction measuring rubber attached strip
(50) without detaching the attaching bolt (31) from the main body
of the friction coefficient measurement apparatus (101).
[0028] On the other hand, when friction measuring rubber (50B) of
the road surface friction measuring rubber attached strip (50) has
been worn down, the attaching bolt (31) is loosened (unscrewed) in
a range that it is not detached from the main body of the friction
coefficient measurement apparatus (101), the road surface friction
measuring rubber attached strip (50) that the friction measuring
rubber (50B) thereof has been worn down is moved and the shaft of
the attaching bolt (31) is detached from the attaching bolt
insertion slit (50A) in the road surface friction measuring rubber
attached strip (50). Thereby, it is possible to detach the road
surface friction measuring rubber attached strip (50) that the
friction measuring rubber (50B) thereof has been worn down from the
main body of the friction coefficient measurement apparatus
(101).
[0029] As described above, according to the present invention, when
exchanging the road surface friction measuring rubber attached
strip (30, 50) with the new one, the attaching bolt (31) of the
road surface friction measuring rubber attached strip (30, 50) is
held in a state of being screwed into the main body of the friction
coefficient measurement apparatus (100, 101), and therefore, work
of detaching and screwing the attaching bolt (31) are not
necessary. Therefore, it is not necessary to separately provide a
space for storing the attaching bolt (31) which has been detached
from the main body of the friction coefficient measurement
apparatus (100, 101) while carrying out the work for exchanging the
road surface friction measuring rubber attached strip (30, 50) with
the new one.
[0030] Further, since the attaching bolt (31) is in a state of
being screwed into the main body of the friction coefficient
measurement apparatus (100, 101), the attaching bolt (31) does not
fall from the main body of the friction coefficient measurement
apparatus (100, 101) and the attaching bolt (31) are not lost
although the above-mentioned work for exchanging is carried out at
night.
[0031] In the present invention, the rubber attached strip fall
prevention washer (33) in the annular main body part of which the
notch (33A) is provided (in the circumferential direction) and on
the annular main body part of which the projections (33B) which
project in the radius direction outward are formed is interposed
between the spring washer (32: the existing spring washer) for
anti-loosening the attaching bolt (31) and the bolt head of the
attaching bolt (31). Since the opening size (L1) of the notch (33A)
formed in the rubber attached strip fall prevention washer (33) is
set (slightly) smaller than the outer diameter of the shaft of the
attaching bolt (31), when interposing the rubber attached strip
fall prevention washer (33) between the spring washer (32) and the
bolt head of the attaching bolt (31), the notch (33A) in the rubber
attached strip fall prevention washer (33) is manually forced open
and the shaft (the bolt shaft) of the attaching bolt (31) is
inserted into the forced-open notch (33A).
[0032] Since the forced-open notch (33A) is elastically deformed,
after the shaft (the bolt shaft) of the attaching bolt (31) has
been inserted into the notch (33A), the size of the opening of the
notch (33A) returns to a state where it is slightly smaller than
the diameter size of the shaft (the bolt shaft) of the attaching
bolt (31) and an inner circumferential surface of the rubber
attached strip fall prevention washer (33) maintains a state of
fastening the attaching bolt (31) with the aid of elastic repulsive
force. Therefore, the rubber attached strip fall prevention washer
(33) is not separated from the attaching bolt (31).
[0033] Then, since the maximum distance (L2) between the leading
ends of the projections (33B) of the rubber attached strip fall
prevention washer (33) is larger than the large diameter of the
attaching bolt insertion opening (30A) in the road surface friction
measuring rubber attached strip (30), even when the road surface
friction measuring rubber attached strip (30) is in a state of
being about to fall downward, the projections (33B) are caught in
the attaching bolt insertion opening (30A) in the road surface
friction measuring rubber attached strip (30). Therefore, the road
surface friction measuring rubber attached strip (30) is prevented
from dropping out or falling downward from the attaching bolt (31)
or the main body of the friction coefficient measurement apparatus
(100, 101).
[0034] In the present invention, when the road surface friction
measuring rubber attached strip (30, 50) is constructed by the
magnetic body (for example, iron) and the rubber attached strip
holding magnet (34) is provided in the vicinity of the attaching
bolt (31), the road surface friction measuring rubber attached
strip (30, 50) is more attracted to the rubber attached strip
holding magnet (34) and therefore the road surface friction
measuring rubber attached strip (30, 50) is more prevented from
being separated from the main body of the friction coefficient
measurement apparatus (100, 101).
[0035] In addition, in the present invention, when the inclinometer
(41) which measures the inclination (of the friction coefficient
measurement apparatus (100, 101)) and the electromagnetic brake
(42) (having the function of stopping the operation of the friction
coefficient measurement apparatus (100, 101)) are included, in a
case where the inclination of at least a predetermined angle has
been measured by the inclinometer (41) in a state where the
friction coefficient measurement apparatus (100, 101) is in
operation, the electromagnetic brake (42) operates and stops the
operation of the friction coefficient measurement apparatus (100,
101).
[0036] In addition, also in a case where the friction coefficient
measurement apparatus (100, 101) which is in operation has been
manually lifted, the inclination of at least the predetermined
angle is measured by the inclinometer (41), the electromagnetic
brake (42) operates and stops the operation of the friction
coefficient measurement apparatus (100, 101).
[0037] Thereby, safety and accuracy in measurement of the friction
coefficient measurement apparatus (110, 101) are secured and the
safety of the operator is secured.
[0038] Then, in the present invention, when a counter (43) (having
the function of measuring and displaying the number of operations
or the number of measurements of the friction coefficient
measurement apparatus (100, 101)) is included, it is possible to
obtain an index for indicating to what extent the friction
measuring rubber (30B, 50B) of the road surface friction measuring
rubber attached strip (30, 50) in the friction coefficient
measurement apparatus (100, 101) is worn down by the number of
times displayed by the counter (43) and therefore it is possible to
grasp the timing of replacing the road surface friction measuring
rubber attached strip (30, 50) with the new one.
[0039] Further, in the present invention, when the satellite
positioning system (44: for example, the global positioning system:
GPS) is included, it is possible to accurately determine a position
where the friction coefficient has been measured.
[0040] In addition, in the present invention, when the road surface
temperature measurement device (45) which measures the temperature
of the road surface is included, it is possible to measure the
temperature of the road surface when measuring the friction
coefficient of the road surface and thereby to determine the
accurate friction coefficient that an important parameter which is
called the road surface temperature has been taken into
consideration.
BRIEF DESCRIPTION OF DRAWINGS
[0041] FIG. 1 is a diagram illustrating one example of an overview
of a friction coefficient measurement apparatus according to one
embodiment of the present invention.
[0042] FIG. 2 is a plan view of the friction coefficient
measurement apparatus illustrated in FIG. 1.
[0043] FIG. 3A is an enlarged explanatory diagram illustrating one
example of a part A in FIG. 2.
[0044] FIG. 3B is an enlarged explanatory diagram illustrating one
example of the part A in FIG. 2.
[0045] FIG. 4A is a diagram illustrating one example of a road
surface friction measuring rubber attached strip used in a first
embodiment of the present invention.
[0046] FIG. 4B is a diagram illustrating one example of the road
surface friction measuring rubber attached strip used in the first
embodiment of the present invention.
[0047] FIG. 5A is an explanatory diagram illustrating one example
of a state where the road surface friction measuring rubber
attached strip illustrated in FIG. 4A and FIG. 4B has been locked
to an attaching bolt.
[0048] FIG. 5B is an explanatory diagram illustrating one example
of the state where the road surface friction measuring rubber
attached strip illustrated in FIG. 4A and FIG. 4B has been locked
to the attaching bolt.
[0049] FIG. 6A is an explanatory diagram illustrating one example
of a state where the road surface friction measuring rubber
attached strip is moved from the state in FIG. 5A and FIG. 5B and
the attaching bolt has been screwed into the main body of the
friction coefficient measurement apparatus.
[0050] FIG. 6B is an explanatory diagram illustrating one example
of the state where the road surface friction measuring rubber
attached strip is moved from the state in FIG. 5A and FIG. 5B and
the attaching bolt has been screwed into the main body of the
friction coefficient measurement apparatus.
[0051] FIG. 7 is a plan view illustrating one example of a rubber
attached strip fall prevention washer used in the first
embodiment.
[0052] FIG. 8 is an explanatory diagram illustrating one example of
a position where the rubber attached strip fall prevention washer
illustrated in FIG. 7 is attached.
[0053] FIG. 9A is an explanatory diagram illustrating one example
of a road surface friction measuring rubber attached strip used in
a second embodiment of the present invention.
[0054] FIG. 9B is an explanatory diagram illustrating one example
of the road surface friction measuring rubber attached strip used
in the second embodiment of the present invention.
[0055] FIG. 10A is an explanatory diagram illustrating one example
of a state where the road surface friction measuring rubber
attached strip illustrated in FIG. 9A and FIG. 9B has been locked
to the attaching bolt.
[0056] FIG. 10B is an explanatory diagram illustrating one example
of the state where the road surface friction measuring rubber
attached strip illustrated in FIG. 9A and FIG. 9B has been locked
to the attaching bolt.
[0057] FIG. 11A is an explanatory diagram illustrating one example
of a state where the road surface friction measuring rubber
attached strip is moved from the state illustrated in FIG. 10A and
FIG. 10B and the attaching bolt has been screwed into the main body
of the friction coefficient measurement apparatus.
[0058] FIG. 11B is an explanatory diagram illustrating one example
of the state where the road surface friction measuring rubber
attached strip is moved from the state illustrated in FIG. 10A and
FIG. 10B and the attaching bolt has been screwed into the main body
of the friction coefficient measurement apparatus.
[0059] FIG. 12 is an explanatory diagram illustrating one example
of the friction coefficient measurement apparatus according to the
first or second embodiment.
MODES FOR CARRYING OUT THE INVENTION
[0060] In the following, preferred embodiments of the present
invention will be described with reference to the appended
drawings.
[0061] First, the friction coefficient measurement apparatuses 100
and 101 to which the present invention is applied will be described
with reference to FIG. 1 and FIG. 2.
[0062] In FIG. 1, the friction coefficient measurement apparatuses
100 (101) according to each embodiment includes a friction
measurement unit 1, a drive unit 2 which is a rotational driving
source and so forth. The friction measurement unit 1 rotates a
shaft 5, a disk-shaped main body 15 and a disk 17 which is a rotor
by a motor 8 via gears 6 and 7. As illustrated in FIG. 2, the main
body 15 and the disk 17 are coupled together in a tangential
direction of the main body 15 by a spring 16.
[0063] As illustrated in FIG. 1, a guide plate 18 and a pen holder
19 which is slidable in a radius direction are disposed on the disk
17. As illustrated in FIG. 2, the pen holder 19 is coupled to the
disk 17 by a spring 20. A pen 21 (FIG. 1) used for recording
measured values on a recording paper 27 is disposed on the center
of the pen holder 19.
[0064] In FIG. 2, an arm 23 is attached to the disk 17 on the side
(on the left side in FIG. 2) opposite to the guide plate 18 and the
arm 23 is coupled to a damper 24. The damper 24 is fixed to the
main body 15 and functions as a damping device which damps a
torsional vibration generated by the disk 17 and the spring 20.
[0065] The road surface friction measuring rubber attached strips
30 (50) (so called "sliders") are attached to a lower surface of
the main body 15 on the same circumference, for example, at three
positions.
[0066] In FIG. 1, when the friction measuring rubber 30B (50B) (of
each of the road surface friction measuring rubber attached strips
30 (50)) comes into contact with a road surface 26, acceleration
which works in a stop direction acts to rotation of the disk-shaped
main body 15 to which the friction measuring rubber 30B (50B) is
integrally attached caused by friction between the friction
measuring rubber 30B (50B) and the road surface 26.
[0067] The acceleration which works in the stop direction also acts
to the disk 17 which rotates by being coupled with the main body 15
via the spring 16 in association with the above-mentioned
operation. On this occasion, torsion corresponding to the magnitude
of the frictional force between the road surface 26 and the
friction measuring rubber 30B (50B) is generated between the main
body 15 and the disk 17. Then, the main body 15 and the disk 17
rotate in synchronization with each other at mutual relative
positions where elastic force of the spring 16 and the friction
force acting to the friction measuring rubber 30B (50B) are
well-balanced.
[0068] A friction coefficient .mu. of the road surface 26 which is
determined in accordance with a tangential velocity V measured by
the friction coefficient measurement apparatus 100 (101) is
proportional to a relative torsion angle .theta. between the main
body 15 and the disk 17 and it is possible to obtain the friction
coefficient .mu. by measuring the relative torsion angle .theta..
In addition, it is possible to express a tangential velocity V (the
measured velocity V) of the friction measurement rubber 30B (50B)
as a function of a displacement amount S (FIG. 2) in the radius
direction of the spring 20.
[0069] When the relative torsion angle .theta. between the main
body 15 and the disk 17 and the displacement amount S in the radius
direction of the spring 20 are recorded by handwriting on the
recording paper 27, it becomes possible to calculate the friction
coefficient .mu. and the measured velocity V from the recorded
torsion angle .theta. and displacement amount S by the friction
coefficient measurement apparatus 100 (101).
[0070] In the illustrated embodiment, a relation between the
tangential velocity V of the friction measuring rubber 30B (50B) of
the road surface friction measuring rubber attached strip 30 (50)
and the displacement amount S of the spring 20 and a relation
between the friction coefficient .mu. and the relative torsion
angle .theta. are calibrated in advance and thereby it is possible
to automatically record the friction coefficient .mu. of the road
surface 26 and the relative velocity V on the recording paper 27
and it is possible to obtain a change in friction coefficient .mu.
ranging from a high velocity to a low velocity by one-time
measurement.
[0071] As mentioned above, the friction measuring rubber 30B (50B)
of the road surface friction measuring rubber attached strip 30
(50) is the consumption article. Accordingly, when measurement of
the road surface friction is repetitively performed and the rubber
is worn down due to the friction between the rubber 30B (50B) and
the road surface 26, it is requested to replace the road surface
friction measuring rubber attached strip 30 (50) that the friction
measuring rubber 30B (50B) thereof has been worn down with the new
one.
[0072] The part A in FIG. 2 is a place where the road surface
friction measuring rubber attached strip 30 (50) is attached to the
disk-shaped main body 15 of the friction coefficient measurement
apparatus 100 (101) and the attaching bolt 31 is provided on the
attachment place A.
[0073] In FIG. 3A and FIG. 3B, the attaching bolt 31 is screwed
into a holder 35 which is fixed to the main body 15 (see FIG. 1 and
FIG. 2: not illustrated in FIG. 3A and FIG. 3B) and thereby
attaches the road surface friction measuring rubber attached strip
30 (50) (not illustrated in FIG. 3A and FIG. 3B) (to the main body
15). In FIG. 3A and FIG. 3B, a symbol 36 denotes a bolt which fixes
the holder 35 to the main body 15 side.
[0074] A rubber attached trip attachment part 35A is formed on the
center (the center in a crosswise direction in FIG. 3A) of the
holder 35. Parts 35B on the both sides of the rubber attached strip
attachment part 35A (the right and left sides of the rubber
attached strip attachment part 35A in FIG. 3A) are formed as
members of a uniform thickness. On the other hand, the thickness of
the rubber attached strip attachment part 35A is not uniform as
illustrated in FIG. 3B and the thickness is gradually reduced
linearly from one end (a lower end in FIG. 3B) toward the other end
(an upper end in FIG. 3B).
[0075] A screw hole 35C (FIG. 3B) is formed in the center (the
center in the crosswise direction in FIG. 3A) of the rubber
attached strip attachment part 35A of the holder 35 so as to screw
the attaching bolt 31 into the screw hole 35C. The rubber attached
strip attachment part 35A is inclined relative to a bottom surface
35D (an attachment surface to the main body 15 side: extending in a
vertical direction in FIG. 3B) of the holder 35 as illustrated in
FIG. 3B.
[0076] In FIG. 3A, the rubber attached strip holding magnet 34 is
provided in the vicinity of the attaching bolt 31 (the attachment
place A in FIG. 2: under the attaching bolt 31 in FIG. 3A and FIG.
3B) and attracts the road surface friction measuring rubber
attached strip 30 (50) which is constructed by the magnetic body
(for example, iron) other than the rubber part. Even in a case
where the attaching bolt 31 has been detached (unscrewed) from the
screw hole 35C, the road surface friction measuring rubber attached
strip 30 (50) is attracted to the rubber attached strip holding
magnet 34 and therefore separation (falling) of the road surface
friction measuring rubber attached strip 30 (50) from the main body
15 is prevented.
[0077] The rubber attached strip holding magnet 34 is embedded in
the rubber attached strip attachment part 35A of the holder 35 and
the shape thereof may be cylindrical as illustrated in FIG. 3A and
FIG. 3B or may be rectangular parallelepiped (not illustrated).
[0078] A situation where the road surface friction measuring rubber
attached strip 30 is attached to the friction coefficient
measurement apparatus 100 by the attaching bolt 31 in a first
embodiment of the present invention will be described with
reference to FIG. 4A, FIG. 4B, FIG. 5A, FIG. 5B, FIG. 6A, FIG. 6B,
FIG. 7 and FIG. 8.
[0079] As illustrated in FIG. 4A and FIG. 4B, the friction
measuring rubber 30B is attached to one end (a lower end in FIG. 4A
and FIG. 4B) of the road surface friction measuring rubber attached
strip 30 by a well-known manner (for example, adhesion, welding and
so forth) and the vicinity of the other end (an upper end in FIG.
4A and FIG. 4B) of the road surface friction measuring rubber
attached strip 30 is constructed as an attachment part to the main
body 15 side.
[0080] When the friction measuring rubber 30B is worn down, the
road surface friction measuring rubber attached strip 30 that the
friction measuring rubber 30B thereof has been worn down is
exchanged with the new one (another road surface friction measuring
rubber attached strip 30 that the friction measuring rubber 30B
thereof is not worn down).
[0081] As illustrated in FIG. 4B, the friction measuring rubber 30B
is gradually increased in thickness toward a leading end (the
rubber 30B side end: the lower end in FIG. 4B) of the road surface
friction measuring rubber attached strip 30 and has a sufficient
thickness in the vicinity of the leading end thereof.
[0082] As illustrated in FIG. 4A, the insertion opening 30A into
which the attaching bolt 31 is to be inserted is formed in the
attachment part in the vicinity of the other end of the road
surface friction measuring rubber attached strip 30 (the end which
is opposite to the end to which the rubber 30B is attached: the
upper end in FIG. 4A).
[0083] The attaching bolt insertion opening 30A is formed into a
shape obtained by overlapping the circles of different diameter
sizes, the small-diameter circular part 30AB is disposed on the
upper part (in FIG. 4A) and the large-diameter circular part 30AA
is disposed on the lower part (in FIG. 4A).
[0084] The diameter of the large-diameter circular part 30AA is set
slightly larger than the diameter of the bolt head of the attaching
bolt 31 and the diameter of the small-diameter circular part 30AB
is set smaller than the diameter of the bolt head of the attaching
bolt 31 and slightly larger than the diameter of the bolt shaft
thereof.
[0085] When attaching the road surface friction measuring rubber
attached strip 30 to the main body 15, the bolt head of the
attaching bolt 31 is inserted into the large-diameter circular part
30AA of the attaching bolt insertion opening 30A in the road
surface friction measuring rubber attached strip 30 and the road
surface friction measuring rubber attached strip 30 is caught on
(locked to) the attaching bolt 31. At this time, the vicinity of
the end on the attachment part side (the side opposite to the
rubber 30B) of the road surface friction measuring rubber attached
strip 30 faces the rubber attached strip attachment part 35A of the
holder 35. In FIG. 5A, the rubber attached strip attachment part
35A is located behind the road surface friction measuring rubber
attached strip 30. Since the rubber attached strip attachment part
35A is not illustrated in FIG. 5A, a leader line of the symbol
"35A" is indicated by a dotted line).
[0086] The road surface friction measuring rubbed attached strip 30
is moved (pulled) from the state illustrated in FIG. 5A in an arrow
B direction (downward in FIG. 5A) in FIG. 5A and the shaft of the
attaching bolt 31 is positioned in the small-diameter circular part
30AB (the upper part of the opening 30A) of the attaching bolt
insertion opening 30A (a state in FIG. 6A and FIG. 6B). The
attaching bolt 31 is fastened in the state in FIG. 6A and FIG. 6B
and thereby the road friction measuring rubber attached strip 30 is
attached to the main body 15 of the friction coefficient
measurement apparatus 100 via the holder 35.
[0087] The attaching bolt 31 and the rubber attached strip
attachment part 35A of the holder 35 are disposed so as to be
inclined relative to the bottom surface 35D which is the attachment
surface of the holder 35 to the main body 15 side as mentioned
above with reference to FIG. 3B. Accordingly, in FIG. 6B which
illustrates a state where the road surface friction measuring
rubber attached strip 30 is attached to the holder 35, the friction
measuring rubber 30B which is provided on a leading end of the road
surface friction measuring rubber attached strip 30 is disposed
closer to the not illustrated road surface relative to the
attachment surface (the bottom surface 35D of the holder 35) on the
main body 15 side. Here, the left side in FIG. 6B is the road
surface side.
[0088] When detaching the road surface friction measuring rubber
attached strip 30 that the friction measurement rubber 30B thereof
has been worn down, the attaching bolt 31 is loosened (unscrewed)
in a range that the attaching bolt 31 is not detached from the
holder 35 in FIG. 6A. Then, the road surface friction measuring
rubber attached strip 30 is moved in an arrow C direction in FIG.
6A (upward in FIG. 6A) so as to position the bolt head of the
attaching bolt 31 in the large-diameter circular part 30AA of the
attaching bolt insertion opening 30A as illustrated in FIG. 5A.
Then, the road surface friction measuring rubber attached strip 30
is moved (pulled up) in a direction vertical to the drawing of FIG.
5A and in a spectator-side direction such that the attaching bolt
31 passes through the large-diameter circular part 30AA of the
attaching bolt insertion opening 30A and thereby the road surface
friction measuring rubber attached strip 30 is detached from the
main body of the friction coefficient measurement apparatus
100.
[0089] According to the illustrated first embodiment, since the
road surface friction measuring rubber attached strip 30 is
attached to and detached from the main body of the friction
coefficient measurement apparatus 100 in the above-mentioned
manner, when performing the work of replacing the road surface
friction measuring rubber attached strip 30 with the new one, the
attaching bolt 31 is held in a state of being not detached from the
holder 35 (in a state of being screwed into the holder 35) and
therefore it is not requested to perform the work of unscrewing the
attaching bolt 31, detaching the attaching bolt 31 and then again
screwing the attaching bolt 31 into the holder 35 (after the road
surface friction measuring rubber attached strip 30 has been
attached or detached). Therefore, it is not requested to separately
provide the space for storing the attaching bolt 31 which has been
detached from the main body 15 side while performing the work of
replacing the road surface friction measuring rubber attached strip
30 with the new one and also management man-day for provision of
the space is not taken.
[0090] Further, since the attaching bolt 31 is in a state of being
screwed to the main body 15 side, the attaching bolt 31 does not
fall from the main body 15 side and there is no fear of losing the
attaching bolt 31 even in the night work.
[0091] In addition, since the road surface friction measuring
rubber attached strip 30 is attracted to the rubber attached strip
holding magnet 34, separation of the road surface friction
measuring rubber attached strip 30 from the main body 15 side is
prevented.
[0092] In addition, since the road surface friction measuring
rubber attached strip 30 is attached to the main body 15 of the
friction coefficient measurement apparatus 100 via the holder 35,
it is possible to select a distance between the friction measuring
rubber 30B and the road surface 26 and a contact angle of the
friction measuring rubber 30B relative to the road surface 26 by
appropriately setting the inclination of the bottom surface 35D
(the attachment surface) of the rubber attached strip attachment
part 35A of the holder 35.
[0093] Here, when the road surface friction measuring rubber
attached strip 30 is moved relative to the attaching bolt 31 for
some reason and the attaching bolt 31 is positioned in the
large-diameter circular part 30AA of the attaching bolt insertion
opening 30A, it is feared that the road surface friction measuring
rubber attached strip 30 may fall from the main body 15.
[0094] Although not clearly illustrated in FIG. 5A, FIG. 5B, FIG.
6A and FIG. 6B, in the illustrated first embodiment, the spring
washer 32 (the existing spring washer) for anti-loosening the
attaching bolt 31 is provided (see FIG. 8).
[0095] In addition, in the illustrated first embodiment, in order
to prevent the road surface friction measuring rubber attached
strip 30 from dropping out of the main body 15 side of the friction
coefficient measurement apparatus 100, the rubber attached strip
fall prevention washer 33 is provided as illustrated in FIG. 7 and
FIG. 8.
[0096] In FIG. 7, the rubber attached strip fall prevention washer
33 has the main body part which is annular as a whole and the notch
33A is formed in one part of the main body part in its
circumferential direction. Then, the plurality (four) of
projections 33B which project outward in the radius direction are
formed on the main body part at equally separated positions in its
circumferential direction.
[0097] The opening size L1 of the notch 33A is set (slightly)
smaller than the outer diameter of the shaft of the attaching bolt
31 and the distance L2 between the leading ends of the two
projections 33B which are disposed at mutually facing positions is
set larger than the diameter of the large-diameter circular part
30AA (see FIG. 4A) of the attaching bolt insertion opening 30A in
the road surface friction measuring rubber attached strip 30.
[0098] The diameter of the inner circumferential surface of the
rubber attached strip fall prevention washer 33 is set the same as
the diameter of the inner circumferential surface of the existing
spring washer 32.
[0099] As illustrated in FIG. 8, the rubber attached strip fall
prevention washer 33 is interposed between the existing spring
washer 32 and the bolt head of the attaching bolt 31. Then, the
rubber attached strip fall prevention washer 33 is set to a size
which makes it possible to nip and hold the rubber attached strip
fall prevention washer 33 by the existing spring washer 32 and the
bolt head of the attaching bolt 31.
[0100] In FIG. 8, the rubber attached strip fall prevention washer
33 and the existing spring washer 32 are interposed between the
bolt head of the attaching bolt 31 and the road surface friction
measuring rubber attached strip 30 and the rubber attached strip
fall prevention washer 33 is interposed between the existing spring
washer 32 and the bolt head of the attaching bolt 31.
[0101] When disposing the rubber attached strip fall prevention
washer 33 between the existing spring washer 32 and bolt head of
the attaching bolt 31, the notch 33A (FIG. 7) is pressed in a
diameter expanding direction and is elastically deformed to such an
extent that the opening size L1 of the notch 33A becomes larger
than the diameter size of the shaft (the bolt shaft) of the
attaching bolt 31 and the shaft of the attaching bolt 31 is
inserted through the notch 33A.
[0102] After the shaft (the bolt shaft) of the attaching bolt 31
has been inserted through the notch 33A, pressing of the notch 33A
(FIG. 7) in the diameter expanding direction is stopped. Thereby,
the opening of the notch 33A is returned to a state of being
slightly smaller than the diameter size of the shaft (the bolt
shaft) of the attaching bolt 31 with the aid of the elastic
repulsive force of the rubber attached strip fall prevention washer
33. As a result, since the inner circumferential surface of the
rubber attached strip fall prevention washer 33 maintains a state
of fastening the attaching bolt 31 with the aid of the elastic
compulsive force, the road surface friction measuring rubber
attached strip 30 is not separated from the attaching bolt 31.
[0103] As mentioned above, the maximum distance L2 between the
leading ends of the two facing projections 33B of the rubber
attached strip fall prevention washer 33 is set larger than the
diameter of the large-diameter circular part 30AA of the attaching
bolt insertion opening 30A in the road surface friction measuring
rubber attached strip 30. Therefore, even in a case where the road
surface friction measuring rubber attached strip 30 is in a state
of being about to fall (upward in FIG. 8), the projections 33B are
caught in the attaching bolt insertion opening 30A in the road
surface friction measuring rubber attached strip 30.
[0104] Therefore, the road surface friction measuring rubber
attached strip 30 does not drop out of the attaching bolt 31 or
does not fall downward.
[0105] Next, a second embodiment of the present invention will be
described with reference to FIG. 9A, FIG. 9B, FIG. 10A, FIG. 10B,
FIG. 11A and FIG. 11B. More specifically, in the second embodiment,
a manner of attaching the road surface friction measuring rubber
attached strip 50 to the friction coefficient measurement apparatus
101 by the attaching bolt 31 will be described.
[0106] The friction coefficient measurement apparatus 101 according
to the second embodiment is different from the friction coefficient
measurement apparatus 100 according to the first embodiment in the
constructions of the road surface friction measuring rubber
attached strip 50. In addition, the friction coefficient
measurement apparatus 101 according to the second embodiment does
not include the rubber attached strip fall prevention washer 33 in
the first embodiment.
[0107] As illustrated in FIG. 9A and FIG. 9B, the friction
measuring rubber 50B is attached to one end (the lower end in FIG.
9A and FIG. 9B) of the road surface friction measuring rubber
attached strip 50 used in the second embodiment by the well-known
manner (for example, adhesion, welding and so forth). The vicinity
of the other end (the upper end in FIG. 9A and FIG. 9B) of the road
surface friction measuring rubber attached strip 50 is constructed
as an attachment part to the main body 15 side. The friction
measuring rubber 50B according to the second embodiment has
constructions and characteristics which are the same as those of
the friction measuring rubber 30B of the road surface friction
measuring rubber attached strip 30 according to the first
embodiment.
[0108] Similarly to the case of the first embodiment, when the
friction measuring rubber 50B has been worn down, the road surface
friction measuring rubber attached strip 50 that the friction
measuring rubber 50B thereof has been worn down is replaced with
the new one (another road friction measuring rubber attached strip
50 that the friction measuring rubber 50B thereof is not worn
down.
[0109] As illustrated in FIG. 9A, the attaching bolt insertion slit
50A into which the attaching bolt 31 is to be inserted is formed in
the attachment part in the vicinity of the other end (the end which
is opposite to the end that the friction measuring rubber 50B is
attached: the upper end in FIG. 9A) of the road surface friction
measuring rubber attached strip 50.
[0110] The attaching bolt insertion slit 50A is formed from one
side surface (a right side surface in FIG. 9A) of the road surface
friction measuring rubber attached strip 50 toward the leftward
center side and is formed in a direction vertical to a longitudinal
direction of the road surface friction measuring rubber attached
strip 50.
[0111] The attaching bolt insertion slit 50A includes an insertion
part 50AA which is formed from one side surface (the right side
surface in FIG. 9A) of the road surface friction measuring rubber
attached strip 50 toward the center side (leftward in FIG. 9A) up
to the widthways center (of the road surface friction measuring
rubber attached strip 50) having a predetermined width size and a
semicircular central part 50AB which is formed contiguously to the
insertion part 50AA and has a predetermined diameter size on the
widthways center (of the road surface friction measuring rubber
attached strip 50).
[0112] Here, both of the width size of the insertion part 50AA and
the diameter size of the central part 50AB of the attaching bolt
insertion slit 50A are set sizes which are smaller than the
diameter of the bolt head of the attaching bolt 31 and slightly
larger than the diameter of the bolt shaft thereof.
[0113] The road surface friction measuring rubber attached strip 50
is attached to the main body 15 (see FIG. 1 and FIG. 2) of the
friction coefficient measurement apparatus 101 via the holder 35
which is the same as that which has been mentioned above with
reference to FIG. 3A and FIG. 3B and so forth similarly to the
first embodiment.
[0114] When attaching the road surface friction measuring rubber
attached strip 50 to the main body 15, the shaft of the attaching
bolt 31 is inserted through (the end opening of) the insertion part
50AA of the attaching bolt insertion slit 50A in the road surface
friction measuring rubber attached strip 50 as illustrated in FIG.
10A and FIG. 10B. At this time, the attaching bolt 31 is in a state
of being loosened to such an extent that it does not detach from
the holder 35 (being fixed to the main body 15).
[0115] In the state in FIG. 10A and FIG. 10B, the vicinity of the
end on the attachment part side (the side opposite to the friction
measuring rubber 50B) of the road surface friction measuring rubber
attached strip 50 is not in close contact with the rubber attached
strip attachment part 35A of the holder 35.
[0116] Then, the road surface friction measuring rubber attached
strip 50 is moved in an arrow D direction (rightward in FIG. 10A)
in FIG. 10A relative to the attaching bolt 31 and the shaft of the
attaching bolt 31 is relatively moved leftward along the insertion
part 50AA of the attaching bolt insertion slit 50A so as to
position the shaft of the attaching bolt 31 on the widthways center
of the road surface friction measuring rubber attached strip 50. On
this occasion, (the shaft of) the attaching bolt 31 abuts on the
center-side end (that is, the end of the center part 50AB) of the
attaching bolt insertion slit 50A and is positioned.
[0117] In this state, (the shaft of) the attaching bolt 31 is
positioned on the center part 50AB of the attaching bolt insertion
slit 50A and the vicinity of the end on the attachment part side
(the side opposite to the friction measuring rubber 50B) of the
road surface friction measuring rubber attached strip 50 is in
close contact with the rubber attached strip attachment part 35A of
the holder 35 (a state in FIG. 11A and FIG. 11B).
[0118] The road surface friction measuring rubber attached strip 50
is attached to the main body 15 of the friction coefficient
measurement apparatus 101 via the holder 35 by fastening the
attaching bolt 31 in the state in FIG. 11A and FIG. 11B.
[0119] Incidentally, since, also in the second embodiment, the
rubber attached strip holding magnet 34 is embedded in the rubber
attached strip attachment part 35A of the holder 35 and the road
surface friction measuring rubber attached strip 50 whose part
other than the friction measuring rubber 50B is constructed by the
magnetic body is attracted to the rubber attached strip holding
magnet 34 as illustrated in FIG. 10A, FIG. 10B, FIG. 11A and FIG.
11B similarly to the first embodiment, separation of the road
surface friction measuring rubber attached strip 50 from the main
body 15 side is prevented.
[0120] When detaching the road surface friction measuring rubber
attached strip 50 that the friction measuring rubber 50B thereof
has been worn down from the main body 15, the attaching bolt 31 is
loosened (unscrewed) in a range that the attaching bolt 31 is not
detached from the holder 35 in FIG. 11A and FIG. 11B. Then, the
road surface friction measuring rubber attached strip 50 is moved
in an arrow E direction (leftward in FIG. 11A) in FIG. 11A and the
shaft of the attaching bolt 31 is detached from the attaching bolt
insertion slit 50A in the road surface friction measuring rubber
attached strip 50. On this occasion, detachment is performed while
avoiding interference with the part 35B which is larger in
thickness than the rubber attached strip attachment part 35A by
pulling upward the left-side end of the road surface friction
measuring rubber attached strip 50 in the direction vertical to the
drawing and in the spectator-side direction.
[0121] It is possible to detach the road surface friction measuring
rubber attached strip 50 that the friction measuring rubber 50B
thereof has been worn down from the main body 15 of the friction
coefficient measurement apparatus 101 in this way.
[0122] Other constructions and operational effects of the second
embodiment illustrated in FIG. 9A, FIG. 9B, FIG. 10A, FIG. 10B,
FIG. 11A and FIG. 11B are the same as those of the first embodiment
illustrated in FIG. 1, FIG. 2, FIG. 3A, FIG. 3B, FIG. 4A, FIG. 4B,
FIG. 5A, FIG. 5B, FIG. 6A, FIG. 6B, FIG. 7 and FIG. 8.
[0123] Next, points of the friction coefficient measurement
apparatuses 100 (101) according to the illustrated first and second
embodiments which are different from those of the related art
friction coefficient measurement apparatus (the Patent literature 1
and so forth) will be mainly described with reference to FIG.
12.
[0124] In FIG. 12, the friction coefficient measurement apparatus
100 (101) includes the inclinometer 41. An article on the market
(for example, a brand name "DS Series" manufactured by NKK SWITCHES
CO. LTD.) may be used as the inclinometer 41.
[0125] The inclinometer 41 has the function of measuring the
inclination of the whole friction coefficient measurement apparatus
100 (101). A measurement result obtained from the inclinometer 41
is sent to the electromagnetic brake 42 via a not illustrated
signal transfer line.
[0126] In FIG. 12, the driving motor 8 rotates the friction
measurement unit 1 via the gears 6 and 7 and the shaft 5. Then, the
road surface friction measuring rubber attached strips 30 (50) are
attached onto the lower surface of the main body 15 of the friction
measurement unit 1, for example, at three positions.
[0127] Although not clearly illustrated in FIG. 12, the
electromagnetic brake 42 has the function that in a case where the
inclination of the friction coefficient measurement apparatus 100
(101) which is at least a predetermined angle has been measured by
the inclinometer 41 in a state where the friction coefficient
measurement apparatus 100 (101) is in operation, (the
electromagnetic brake 42) operates and stops the operation of the
friction coefficient measurement apparatus 100 (101).
[0128] In addition, the electromagnetic brake 42 also has the
function that in a case where the friction coefficient measurement
apparatus 100 (101) which is in operation has been lifted manually,
the electromagnetic brake 42 operates and stops the operation of
the friction coefficient measurement apparatus 100 (101).
[0129] In addition, the friction coefficient measurement apparatus
100 (101) according to the illustrated embodiment includes the
counter 43. The counter 43 has the function of measuring and
displaying the number of operations or the number of measurements
of the friction coefficient measurement apparatus 100 (101).
[0130] The number of operations or the number of measurements which
is displayed on the counter 43 serves as the index for indicating
to what extent the friction measuring rubber 30B (50B) of the road
surface friction measuring rubber attached strip 30 (50) in the
friction coefficient measurement apparatus 100 (101) is worn down
and it is possible for a user of the friction coefficient
measurement apparatus 100 (101) to grasp the timing of replacing
the road friction measuring rubber attached strip 30 (50) with the
new one.
[0131] Further, in the illustrated embodiment, the friction
coefficient measurement apparatus 100 (101) includes the satellite
positioning system 44 (for example, the global positioning system:
GPS). Although illustration is omitted, position information of the
friction coefficient measurement apparatus 100 (101) determined by
the satellite positioning system 44 is sent to a processing device
in the friction coefficient measurement apparatus 100 (101) or an
externally disposed processing system and thereby it becomes
possible to accurately determine the position where the friction
coefficient has been measured by the friction coefficient
measurement 100 (101).
[0132] The friction coefficient measurement apparatus 100 (101)
according to the illustrated embodiment also includes the road
surface temperature measurement device 45. The road surface
temperature measurement device 45 has the function of measuring the
road surface temperature when measuring the friction coefficient of
the road surface. Therefore, it is possible to determine the
accurate friction coefficient by analyzing the influence of the
road surface temperature imposed on the friction coefficient of the
road surface and taking the road surface temperature into
consideration.
[0133] It is to be additionally noted that the illustrated
embodiments are merely illustrative and are not described with the
intention of limiting the technical scope of the present invention.
For example, friction coefficient measurement apparatuses of the
types other than those illustrated in FIG. 1 and FIG. 2 are also
applicable.
DESCRIPTION OF REFERENCE NUMERALS OR SYMBOLS
[0134] 30, 50 . . . road surface friction measuring rubber attached
strip [0135] 30A . . . attaching bolt insertion opening [0136] 30AA
. . . large-diameter circular part (of the opening) [0137] 30AB . .
. small-diameter circular part (of the opening) [0138] 31 . . .
attaching bolt [0139] 32 . . . anti-loosening spring washer
(existing spring washer) [0140] 33 . . . rubber attached strip fall
prevention washer [0141] 33A . . . notch [0142] 33B . . .
projection [0143] 34 . . . rubber attached strip holding magnet
[0144] 41 . . . inclinometer [0145] 42 . . . electromagnetic brake
[0146] 43 . . . counter [0147] 44 . . . satellite positioning
system [0148] 45 . . . road surface temperature measurement device
[0149] 50A . . . attaching bolt insertion slit [0150] 100, 101 . .
. friction coefficient measurement apparatus
* * * * *